Mechanisms of corrosive behavior of L80-13Cr steel in simulated CO2 sequestration wellbore casing-cement in environment containing impure supercritical CO2

摘要

Given the risks of casing corrosion failure and CO 2 leakage at the casing -cement interface in CO 2 sequestration technology, along with the limited purity of carbon sources and the unclear corrosion mechanisms and crevice corrosion sensitivity of L80-13Cr in this system, this study investigate d the corrosion behavior and crevice corrosion sensitivity of L80 -13Cr in a simulated cement pore solution environment containing impurities (SO2, NO2, O2) at 10 MPa and 80° C. The results indicated that, in the absence of crevice structures, carbon source impurities had no significant impact on corrosion behavior of L80 -13Cr steel, with a very low uniform corrosion rate. The surface of t he samples was predominantly covered by protective Cr -containing products.. However, notable pitting behavior is observed. In the presence of crevice structures, localized corrosion occurred within the crevice. Additionally, pitting was more pronounced tha n in the absence of crevices. Besides Cr -containing products, FeCO3 was also formed within the crevice. The introduction of different concentrations of impurity gases did not significantly alter the crevice corrosion behavior, which may be related to the C a2+-rich environment and the interactions between the impurity gases. The destabilization and failure of the passivation film within the crevice pose a potential risk of crevice corrosion failure and CO2 leakage for L80-13Cr in this system.